Means of wet screen sizing



Oct. 2, 1951 W C. LAUGHUN 2,570,035

MEANS OF' WET SCREEN SIZING Filed Feb. 28, 1949 I Caz INVENTOR.

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Patented Oct. 2, 1951 UNITED STATES PATENT OFFICE 2,570,035 MEANS oF WET SCREEN sIzING William o. Laughlin, New York, N. Y. l Application February 2s, 1949, serial No. 78,780

l 1 Claim.

The invention relates to screening of ground minerals.

The object of the invention is to split a ground mineral oi mixed sizes into plus and minus screen sizes, and thus scalp the finer sizes from the coarser sizes.

Present commercial wet screening of minerals is conducted on an inclined screen surface, with the particles assisted in downward movement by vibration, repulping and water sprays. Its disadvantages, especially with screens of 48 mesh and smaller mesh are small capacity, blinding of the screen openings, and screen wear due to abrasion. Other processes have many disadvantages.

The improvement of screen sizing of ground minerals consists in passing the mineral of mixed sizes into an uprising flow of water, above diifusion members, and below a screen of dened mesh, and by the action of the uprising flow of water cause the flow with the mineral particles smaller than the screen mesh to pass towards and against the under surface of the screen and through its openings in water suspension and to separate recovery, while causing the mineral particles of sizes larger than the screen mesh which collect below the screen to move from the entrance and at right angles to the upward flow of water, by increase in density, to a discharge.

The improvement is applicable to minerals whose largest size can be maintained in teeter movement or action by the uprising ilow of water which carries the minus sizes towards the under surface of the screen and through the same.

The invention includes a novel apparatus, which consists in a diffusion member with a screen of the size necessary to carry out the desired screening spaced from the diffusion member, both parallel to each other and both horizontally disposed, with the water ascending at right angles thereto, and with the minerals of mixed sizes entering one part of the said space and with the larger sizes passing through the space by density increase, while the smaller sizes are carried by the ascending water through the screen openings from below to above the screen.

The invention will be more fully described hereinafter, an embodiment thereof shown in the drawings, and the invention will be iinally pointed out in the claim.

In the accompanying drawings,

Fig. l is a vertical longitudinal section of one embodiment of my invention;

Fig. 2 is a plan view taken on the line 2 2 of Fig. 1;

Fig. 3 is a side View;

Fig. 4 is a left hand end view with a detail view of the screen tappet assembly, and Fig. 5 is a detail view of the screen tappet assembly, taken at a right angle to the view shown in Fig. 4.

Similar characters of reference indicate corresponding parts throughout the various views. Referring to the drawings,`generally considered, the invention embodies the concept of feeding the minerals to the under surface of a substantially horizontally disposed screen of suitable mesh to allow only particles of predetermined sizes to pass therethrough, and the particles of other sizes to be carried away from the screen zone. These may be again separated by a repetition of said hydraulic screening in a, separate apparatus, but the meshes of the screen would then be larger or smaller. The hydraulic screening action takes place by a mix of different sizes entering an ascending now of water, which by the continuation of the feeding of the mix causes the larger particles to move onward towards their discharge, While the ner particles pass through the open spaces of the screen from its bottom surface to above the screen to their discharge.

The operation is conducted in a rectangular container III having bottom, side and end walls II, I2 and I3.

At the lower elevation of the container isa water compartment I5, with water inlet pipe VI E having a cap I1 and outlet holes I8 preferably at the bottom of the pipe, within the compartment and a control valve I9 and extension 20 to water supply, without the container. The upper elevation of this water compartment I5 is formed by a diffusion member 25 of porous plates 2E, having a supporting frame 2l, and end Walls 28. The porous plates prevent settling upon their upper surface due to the multiplicity of Water ejections merging into each other into one common upward flow.

Adjacent to this water compartment I5 is a second water compartment 3|] formed of walls 38 and 39, vertically divided by a diiusion member 35 of porous plate 3I supported on a frame 31.

A water pipe 40 having a cap 4I and. holes 42 is within the compartment, and control valve 43 and pipe extension 44 are without the compartment, with this pipe extension 44 connected to the water supply pipe 20.

Above the diffusion plate 3| of the water compartment 30 are L shaped outlet pipes 4l, with an inlet 48 above the diffusion plate 3| and outlet 49 outside of the compartment 30.

Attached to the end wall I3 is a chamber 50 with outlet 5I at its bottom for receiving and discharging the oversize.

At the end of container opposite chamber 50, a feed chamber 60 is provided and dened by Walls I3, I2 and 6I. Above the area, of the diffusion member E5, but exclusive of that portion of the area defined by the feed chamber 60 is suspended a screen ll), supported by and attached to the Walls I3 and 6I.

Attached to the screen I0 is a, steel block 1I, above which is a tappet 'I2 actuated in its upward movement by cams T3 and lll, attached to a shaft l5 of a gear motor 16, and actuated in its downward movement by a spring 11 and guided by a hole V18aY in a motor support 18, and by an upper support T9 which in turn is attached to motor support 18. The helical spring 'Il is placed between two washers lla and 11b, one of which, 1lb, is secured to the tappet l2. A top T80 is supported by the upper ends of' the Ywalls l3and6l.

Attached to the sides of the container along its length, with its upper elevation just below'the screen level are launders -B and 8 I.

The operation of the apparatus is as follows:

,Water is passed to water chambers I5 and 3 0, and upwardly through the diffusion members 65, 25 and 3'5'v and through the screen le'. Ore in mixed .sizes is then fed to feed chamber te" and the water adjusted atA valvejQ to cause a strong teeter action of the particles and carry theV undersize particles through theY screenl lil and to discharge with the water rising from the screen .and into the launders Vt and 8i, while retaining the oversize particles in teeter movement below the screen, and by the increase in density as they accumulate cause said oversize particles to move to the chamber" 3Q above the diffusion member 3K5, and from this chamber through outlet pipes 4l, and to discharge to receiving chamber 5t and thence tov discharge through outlet pipe l, The screen in the preferred form is given a rapid tapping 'by means of a motor actuated tappet "E2 to assist any mineral particles to pass from its upper surface and ow off with the water;

Comparative tests on nely ground iron ore of 80% minus 100 mesh have shown a capacity of over twenty times that of the inclined down flow apparatus, per square foot of screen area, Vand lwith no' blinding of the meshes.

The method consists in subjecting particles of various sizes to a teetering action in an ascending c liffused` flow of water, to enable the heavier particles to move horizontally and out of the path of the ascending diffusion now of water, and 'to'have it carry the finer particles through the openings of a screen from its lower surface to above' its' upper surface, to separate them from the heavier particles, and enable them free from said heavier particles to be removed with the overflow of the ascending water. The screen sizes, preferably of the Ton-Cap type No. 2602 ('Ihe W. S. Tyler Company of Cleveland, Ohio), have given satisfaction in removing finer than 100 meshmaterial- But other sizes of screens are suitable for other sizes of particles intended to be separated. The particles smaller than the screen openings are carried through said openings, and then cannot descend through the screen due to the flow of the water then passing through the openings of the screen, which flow carries the separated particles, through the openings and to the launder. There is no Vwear of the screen as heretofore. i

It isto be particularly noted that the improvement` is based on an uprising feed of the particles to the lower surface of the screen with those smaller than the 'screen openings, by a fluid flow passingth'rough the openings, in contrast to a inix'ed feed moving along on the upper surface of a screen.

The teetering movement to which the larger particles are subjected enable them to be continuously and constantly shifted in a general horizontal direction from inlet to discharge, the ner particles having separated from the larger particles by such teetering action, being now free to findtheir `exitup through :thel openings in the screen, those not being able to' pass through following the passage from inlet to outlet of the largest particles of the feed selected, which is gauged by the size of the meshes of the screen. The discharged material can be subjected to another screening in which case other screen openings are provided.

I wish it' to be understood that I do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art. Y l,

In an apparatus for wet screen sizing. o'f'rnineral particles, the combination of. a horizontal container having a horizontal base, and a" porous plate of such porosity Vas to permit water to flow therethrough while retaining mineral ,particles abovev the same, said porous plate being [substantially parallel'withY the base of the container, said porous plate dividing said container to forni a water compartmentbelow the `porous `plate, andy forming the base of -a channel above the porous plate, walls forming a channelV with said base, amineral particle .inlet at one end of the channel, an'outlet at the otherend of! the channel, and means supplying water to thewater compartment for ascentv .through `the porous plate to maintain the particles between .said inlet and 4said. outlet, in tester suspension inthe as cending water above Vsaid base,v with .a-screenlocated above said porous Vplate and extending 1on- -gitudinally along said channel disposed in `contact with said suspended particles moving A:from inlet Vto outlet, saidscreen being disposed-to retain mineral particles larger than the scr-een openings within the channel, and permit mineral particles smaller than the screen openings to pass therethrough, vandrneans agitating the mineral particles adjacent the screen, `whereby mineral 4of mixed j-particle size when fed into said -i-nlet and against the now of 4water rising from the porous plate, will move longitudinally in 'the channel and along the screen from said .inletfa-nd toward the opposed outlet, with particles smaller than the screen openings passing from the cha-nnel and through the screen openings with the uprising water and to discharge,l while lthe particles larger thanthe screen. openings retained within the channel `continue in longitudinal movement to separate discharge at Ythe outlet.

' WILLIAMC. LAUG'l-ILIN.

V1aEFsiamoiss CITED The following references yare Jof record in the le yof this patent:

v UNITED STATES PATENTS' e Number Name Date Y 1,040,804 Stanley Oct.Y 8,1912 1,465,931 Collins I "A11g. 1923 V1,468,261 Collins Sept. 18,1923 1,716,309 Fournier June 4,1929 2,196,451 HOlZel' v r Api". 9, 1940 2,410,637 Darby z Nov. l5, 1946 2,420,180 Laughlin I May 6, 1947 O'I-IElltA REFERENCES Websters New International Dictionary5`2nd edition, 1928, p. 728'. 

